Photographic materials containing polymers



United States Patent 3,536,491 PHOTOGRAPHIC MATERIALS CONTAININGPOLYMERS William W. Rees and William H. Russell, Rochester,

N.Y., assignors to Eastman Kodak Company, Rochester, N.Y., a corporationof New Jersey No Drawing. Filed Nov. 8, 1965, Ser. No. 506,832

Int. Cl. G03c 1/04, 1 78 US. Cl. 96-87 16 Claims ABSTRACT OF THEDISCLOSURE This invention relates to new silver halide photographicelements comprising (A) a water-insoluble interpolymer of (1) units ofan alkyl acrylate, (2) units of a vinyl sulfoester and (3) from 0 to 20%of units of at least one other ethylenically unsaturated polymerizablemonomer that is different from (1) and (2); (B) gelatin; and (C) atleast one other hydrophilic colloid. In one preferred embodiment, thisinvention relates to silver halide emulsions comprising saidwater-insoluble interpolymer, gelatin and at least one other hydrophiliccolloid. In one aspect, photographic elements of this invention haveimproved sensitivity and reduced desensitization due to kink marks.

This invention relates to photographic materials, their preparation anduse. In one of its aspects, this invention relates to a means for bothreducing desensitization due to kink marking and improving thesensitivity of photographic emulsions and elements. In another of itsaspects, this invention relates to improved photographic silver halideemulsions and elements containing a unique combination of at least twohydrophilic colloids and at least one water insoluble vinyl polymer.

The desensitization, i.e., reducing the sensitivity to subsequentexposure, of certain film coatings by improper handling of the coatingsso as to produce kink marking is well known. This problem isparticularly troublesome in high speed negative silver bromoiodideemulsions of the type used in radiography. Antikink agents have beenadded to photographic materials to reduce kink marking. However, suchmaterials often reduce the photographic speed, i.e., the sensitivity, ofthe emulsion to which they are added. It is, of course, desirable toobtain photographic emulsions and elements, particularly those suitedfor use in radiography which exhibit improved antikink as well asincreased photographic speed, i.e., sensitivity. It is evident that ameans for reducing susceptibility of photographic materials to kink markdesensitization while also increasing photographic speed would greatlyenhance the art.

Accordingly, it is an object of this invention to provide photographicemulsions and elements exhibiting improved properties.

Another object of this invention is to provide a means for obtainingimproved antikink and photographic speed in photographic materials.

Still another object of this invention is to provide gelatin,photographic silver halide emulsions and elements which contain a uniquecombination of polymers and which have improved antikink andsensitivity.

Other objects of this invention will become apparent from an examinationof the specification and claims which follow.

In accordance with this invention, it has been found that the use of thecombination of gelatin, another hydrophilic colloid in addition togelatin, and a water insoluble interpolymer, as described herein, inphotographic materials, not only reduces kink mark desensitization butalso improves sensitivity, i.e., photographic speed.

3,536,491 Patented Oct. 27, 1970 One embodiment of this inventionrelates to a gelatin photographic silver halide emulsion exhibitingimproved antikink and sensitivity comprising a hydrophilic colloid otherthan gelatin and a water insoluble interpolymer of (l) at least about65%, by weight, of a monomer haw'ng the formula:

where R is a member selected from the group consisting of hydrogen andmethyl and R is alkyl, (2) up to about 20%, by weight, of a monomerhaving the formula:

where R, is a member selected from the group consisting of hydrogen andalkyl, R has its valence bonds represented in the above formula ondifferent carbon atoms and is a member selected from the groupconsisting of divalent hydrocarbon radicals and divalent aliphatichydrocarbon radicals in which a chain of carbon atoms joining the oxygenand sulfur atoms of the above formula is interrupted by an atom fromGroup VI-A of the Periodic Table having an atomic weight less than about33 and M is a cation and (3) 0 to about 20%, by weight, of apolymerizable ethylenically unsaturated monomer that is different from(1) and (2).

Another embodiment of this invention relates to a photographic elementexhibiting improved antikink and sensitivity comprising a support, atleast one gelatin, photographic silver halide emulsion layer containinga hydrophilic colloid other than gelatin, and incorporated in at leastone layer which is no farther from said support than said emulsionlayer, water insoluble interpolymer of (1) at least about 65%, byweight, of a monomer having the formula:

where R is .a member selected from the group consisting of hydrogen andmethyl and R is alkyl, (2) up to about 20%, by weight, of a monomerhaving the formula:

where R, is a member selected from the group consisting of hydrogen andalkyl, R has its valence bonds represented in the above formula ondifferent carbon atoms and is a member selected from the groupconsisting of divalent hydrocarbon radicals and divalent aliphatic hydrocarbon radicals in which a chain of carbon atoms joining the oxygen andsulfur atoms of the above formula is interrupted by an atom from GroupVI-A of the Periodic Table having an atomic weight less than about 33and M is a cation and (3) 0 to about 20%, by weight, of a polymerizableethylenically unsaturated monomer that is different from (1) and (2).

It is a significant feature of this invention that neither thegelatin-hydrophilic colloid nor the gelatin-water insoluble polymercombination alone give both the increased sensitivity and improvedantikink exhibited by soluble interpolymers described herein to obtainboth reduced kink marking and increased speed, as shown by the workingexamples that follow.

The binding material or vehicle employed in the emulsions and elementsdescribed herein is gelatin, a hydrophilic colloid. A portion of thegelatin is replaced by at least one different hydrophilic colloid suchas water soluble polyacrylamide. While particularly efficacious resultsare obtained with water soluble polyacrylamide, other hydrophiliccolloids can be used in combination with the polyacrylamide or in lieuthereof. Such other hydrophilic colloids which can be employed withgelatin, and with or in place of the preferred polyacrylamide, includeany of the hydrophilic water permeable colloids, particularly thematerials generally employed in the preparation of photographic silverhalide emulsion as binding materials or vehicles, as exemplified bycolloidal albumin, cellulose derivatives, synthetic resins, particularlypolyvinyl compounds and the like. Specific examples include watersoluble polymers such as polysaccharides, e.g., dextran, as disclosed inU.S. Pat. 3,063,- 838, issued Nov. 13, 1962, vinyl polymers, e.g., poly-N-vinyl pyrrolidones, as disclosed in U.S. Pat. 3,043,697, issued July10, 1962, polyvinyl alcohol derivatives, e.g., acid derivatives such assuccinoylated polyvinyl alcohol, as disclosed in Minsk and Abel US. Pat.3,165,412, issued Jan. 12, 1965, proteins, protein derivatives, asdescribed in US. Pat. 2,852,382, issued Sept. 16, 1958 or US. Pat.3,011,890, issued Dec. 5, 1961, cellulose derivatives, e.g.,hydroxyethyl cellulose, as disclosed in 11- lingsworth and Minsk US.Pat. 3,003,878, issued Oct. 10, 1961, and like compounds. Additionalhydrophilic col loids that can be used in the practice of this inventionare polymers containing repeating units having the following where R isa carbon chain of 1 to carbon atoms substituted with 1-3 substituentshaving the formula R being hydrogen or lower alkyl, and R and R eachbeing hydrogen or alkyl groups containing up to 5 carbon atoms, alkoxysubstituted alkyl groups containing up to '5 carbon atoms or hydroxysubstituted alkyl groups containing up to 5 carbon atoms. Preferredpolymers of this type contain repeating units having the followingformula:

I% H :l C-NH(CHZ)HCNHCHZCHZOH where n is an integer from 1 to 5.Polymers of this type can also include monomeric units such as vinylalcohol or other vinyl monomeric units including those represented bythe formula:

-CH2(I3H:| Y

where Y is a photographically inert group such as hydroxy, an estergroup such as acetoxy, an amide group such as N-alkylamido where thealkyl group contains up to 5 carbon atoms, carbamate groups such asOCONHR5COOR6 Where R and R are each carbon chains, preferably alkylene,containing up to 5 carbon atoms. These additional polymers andcopolymers can be prepared by any convenient method suitable for thispurpose. For example, they can be prepared by treating the reactionproduct of poly(vinyl alcohol) and an ester of isocyanato monoorpolybasic fatty acid with an amine. The reaction of the isocyanatocompound with the poly(vinyl alcohol) may be partial or complete, as maybe the reac tion of the amine with the initial reaction product. Apolymer of this type which can be employed in the practice of thisinvention is one which contains, in combined form, monomeric units ofvinyl alcohol, vinyl carboxymethyl carbamate andvinyl-N-fl-hydroxyethylcarbamyl methylcarbamate. The concentration ofhydrophilic colloid (not including gelatin) employed in the practice ofthis invention is subject to wide variation. However, the most suitableconcentrations are generally in the range of about 5 to about 80,preferably about 10 to about 60 percent, by weight, based on gelatin. Inpracticing the invention, the hydrophilic colloid is employed in agelatin photographic silver halide emulsion or in at least one gelatinphotographic silver halide emulsion layer of a photographic element.

As already indicated, the water soluble polyacrylamides are thepreferred hydrophilic colloids employed with gelatin and the waterinsoluble interpolymers in practicing this invention. Water solublepolyacrylamides can be obtained by polymerizing monomeric acrylamideusing any procedure found suitable for this purpose. Typical methods forpreparing Water soluble polyacrylamides are described in Minsk et al.U.S..Pat. 2,486,191, issued Oct. 25, 1959, Lowe et al. US. Pat.2,541,474, issued Feb. 13, 1951, US. Pat. 2,533,166, issued Dec. 5,1950, and Allentoff et al. Belgian Pat. 651,507, issued Aug. 31, 1964.These water soluble polyacrylamides are characterized by a temperaturebelow which their solutions in water precipitate polyacrylamide,Therefore, to get solubility, some of these compounds must be dissolvedin water at elevated temperatures. In general, however, 10 grams ofwater soluble polyacrylamide will dissolve in one liter of water at F.Furthermore, the polyacrylamides can contain, in combined form, not onlyacrylamide groups but also acrylic acid or acrylimide groups, dependingupon their process of preparation. The inherent viscosity of the Waterinsoluble polyacrylamides employed in the practice of this invention issubject to variation but is preferably in the range of about 0.1 toabout 0.6, as determined at 25 C. in water. As used herein, the terminherent viscosity is determined by the formula:

wherein 1 is the inherent viscosity, 1 is the relative viscosity ofwater solution of the polymer divided by the viscosity of the water inthe same units and at the same temperature and c is the concentration ingrams (0.25) for a polymer per 100 cc. of solution.

The interpolymers employed in the practice of this invention are nothydrophilic colloids. They are water insoluble interpolymers which canbe prepared by interpolymerizing at least two monomers, one of which isa sulfoester of an a-methylene carboxylic acid. The sulfoesters employedin the preparation of these interpolymers include one or more of thesulfoesters having the formula:

CH2=Ci ]ORsSOaM 1'1. where R R and M are each as defined hereinbefore.Suitable R groups include hydrogen or any of the alkyl radicals,preferably alkyl radicals containing up to about 12 carbon atoms, often1-8 carbon atoms, as exemplified by methyl, ethyl, propyl, pentyl,octyl, dodecyl, and the like. R has its valence bonds represented in theabove formula on different carbon atoms and can be a hydrocarbon radicalor it can be an aliphatic hydrocarbon radical in which a chain of carbonatoms joining the oxygen and sulfur atoms in the formula shown above isinterrupted by an atom from Group VI-A of the Periodic Table having anatomic weight less than about 33, i.e., at least one O and/or A radicalinterrupts the carbon chain. Where R is hydrocarbon, it can be anyaliphatic, cycloaliphatic or aromatic radical and will generally containup to about 12 carbon atoms. Preferred hydrocarbon R radicals arealkylene radicals, generally those containing 2-4 carbons. R can also bea divalent aliphatic hydrocarbon radical in which there is a O and/or Sradical and generally contains up to 12 carbon atoms. Such R radicalscan, therefore, be saturated or unsaturated, although saturated divalentalkylene groups in which the carbon chain is interrupted by oxygen andsulfur atoms are preferred. Suitable R radicals include, for example,ethylene, 1,3-propylene, 1,2-propylene, tetramethylene, 1,3-isobutylene,pentamethylene, hexamethylene, octamethylene, phenylene, bisphenylene,naphthylene, cyclopentylene, cyclohexylene, 2-butenylene, butynylene,2-0xatrimethylene, 3-thiapentamethylene, and the like. M is a cation, asexemplified by hydrogen, an alkali metal such as sodium or potassium,ammonium, the cation of an organic amine such as triethyl amine,diethanol amine and the like.

The sulfoesters can be prepared using any method known to be suitablefor this purpose. For example, in US. Pat. 2,923,734, issued Feb. 2,1960, it is disclosed that an u-methylene carboxylic acid and analiphatic hydroxy sulfonic acid in the free form are interacted byheating together, optionally while dispersed in an inert liquid mediumcapable of forming an azeotrope with water and while azeotropicallydistilling water out of the reaction mixture to form the correspondingcarboxylate ester. The reaction is generally carried out at atemperature between 50 and 200 C. In US. Pat. 3,024,221, issued Mar. 6,1962, there is disclosed a method for preparing the sulfoesters byreacting the appropriate acyl halide with the salt of the hydroxysulfonic acid, generally at a temperature in the range of about to about200 C., although the particular temperature employed depends upon thenature of the specific reactants. Examples of hydroxy sulfonic acids(and their salts) that can be employed to form the sulfoesters are2-hydroxyethane sulfonic acid, 2-hydroxy-l-propane sulfonic acid,l-hydroxy-2 butane sulfonic acid, 2-hydroxycyclohexane sulfonic acid,p-phenolsulfonic acid, 2-(2-hydroxyethoxy) ethane-l-sulfonic acid,2-(2-hydroxyethylthio)ethane-1- sulfonic acid,4-hydroxy-2-butene-1sulfonic acid, 4-hydroxy-Z-butyne-l-sulfonic acidand the like. tat-Methylene carboxylic acids or acyl halides includeacrylic acid, methacrylic acid, a-butylacrylic acid, acryloyl chloride,methacryloyl bromide, u-hexylacryloyl chloride and the like.

The solid interpolymers employed in the practice of this invention areprepared by copolymerizing at least one sulfoester monomer, as describedabove, with at least one ethylenically unsaturated acrylic ester havingthe formula:

where R is hydrogen or methyl and R is an alkyl radical, desirablycontaining 1-12 carbon atoms and preferably 1-4 carbon atoms. Suitablealkyl radicals include, for example, ethyl, methyl, propyl, pentyl,dodecyl and the like. Suitable monomers include, for example, ethylacrylate, methyl acrylate, butyl acrylate, ethyl methacrylate, octylmethacrylate, and the like. The interpolymers employed in practicingthis invention are water insoluble and contain, in polymerized form, atleast about 65%, preferably about 85 to about 95%, by weight, ofpolymerized acrylic ester of the above formula with up to about 20%,preferably about 5 to about by weight, of sulfoester. If desired, theinterpolymers can also contain no more than about 20%, preferably nomore than about 10%, by weight, of additional ethylenically unsaturatedmonomer. Monomeric units of this latter type include those derived fromone or more different monomers which are copolymerizable with theacrylates, methacrylates and sulfoesters set forth hereinbefore, i.e.,different unsaturated, polymerizable compounds containing one or more--CH=C groups or more particularly, one or more CH =C groups. Usefulwater insoluble polymers are, therefore, interpolymers of the acrylates,methacrylates and sulfoesters as described above, with otherethylenically unsaturated polymerizable monomers which form waterinsoluble addition polymers such as vinyl esters, amide, nitriles,ketones, halides, ethers, 0a,,B- unsaturated acids or esters thereof,olefins, diolefins and the like, as exemplified by acrylonitrile,methacrylonitr'ile, styrene, a-methylstyrene, vinyl chloride, vinylidenechloride, methyl vinyl ketone, vinyl acetate, fumaric, maleic anditaconic esters, 2-chloroethyl vinyl ether, methylenemalonitrile,acrylic acid, methacrylic acid, dimethylaminoethyl methacrylate,N-vinylsuccinimide, N-vinylphthalimide, N-vinylpyrrolidone, butadiene,isoprene, vinylidene cyanide and the like. It is obvious that the natureof the different polymerizable, ethylenically unsaturated compound whichis copolymerized with the acrylates, methacrylates and sulfoesters issubject to wide variation. However, as already indicated, theinterpolymers employed can contain 0 to about 20%, by weight, of suchadditional monomer, in polymerized form. Generally, the interpolymersemployed in the practice of this invention have a molecular weight inthe range of about 5000 to about 500,000 or more.

The temperature at which the water insoluble interpolymers employed inpracticing this invention are prepared is subject to wide variationsince this temperature depends upon such variable features as thespecific monomers used, the duration of heating, pressure employed, andlike considerations. However, the polymerization temperature generallydoes not exceed about 100 C., and most often, is in the range of about50 to about C. The polymerization can be carried out in suitablesolvents or diluents, for example, water or mixtures of water with watermiscible solvents, as exemplified by methanol, ethanol, propanol,isopropyl alcohol, butyl alcohol, and the like. The pressure employed inthe polymerization, if any, is usually only sufiicient to maintain thereaction mixture in liquid form, although either superatmospheric orsubatmospheric pressures can be used. The concentration of polymerizablemonomer in the polymerization mixture can be varied widely withconcentrations up to about 40 percent, by weight, and preferably about20 to about 40 percent, by weight, based on the weight of vehicle beingsatisfactory. Suitable catalyst for the polymerization reaction include,for example, the free radical catalysts, such as hydrogen peroxide,cumene hydroperoxide, water soluble azo type initiators and the like. Inredox polymerization systems the usual ingredients can be employed. Ifdesired, the polymer can be isolated from the reaction vehicle byfreezing, salting out, coagulation or by using other separationprocedures suitable for this purpose. Interpolymers of the type employedin the practice of this invention and a process of preparation aredescribed in US. Pat. 2,914,499, issued Nov. 24, 1959.

The water insoluble interpolymers described herein can be incorporatedin the photographic emulsions and elements using any of the meansusually employed in the photographic field for this purpose. Forexample, the polymers can be conveniently added from solvent solutionsprior to coating. The polymers can also be conveniently incorporated inthe photographic elements by dispersion in gelatin, in some otherhydrophilic colloid or in water rather than by means of solvents. Any ofthe polymers employed in practicing this invention can be added to thephotographic emulsions at any time during manufacture of the emulsions,although the polymers are most conveniently added just prior to coating.The water insoluble interpolymers are generally employed in photographicemulsions at concentrations in the range of about to about 100 grams,preferably about to about 60 grams per mole of silver halide. Whenemployed in a layer which is between the emulsion layer and the supportin photographic elements, for example, in a contiguous or adjacentlayer, the water insoluble interpolymers are generally employed inconcentrations of about to about 300 mg. per foot square of support.This generally corresponds to a concentration of about 10 to about 150%,by weight, of the binding agent, preferably gelatin, employed in thelayer. Gelatin is generally coated in layers between the emulsion layerand the support at concentrations in the range of about 0.25 to about 1g. per square foot of support. In the emulsion layer, gelatin isgenerally coated at a concentration of about to about 200 grams per moleof silver halide.

Any of the gelatin photographic silver halide emulsions can be employedin practicing this invention, including, for example, photographicsilver halide emulsions used in X-ray and camera films and the like.Suitable photographic emulsions contain silver halides such as silverchloride, silver bromide, silver bromoiodide, silver chloroiodide,silver chlorobromide and the like. Photographic emulsions which formlatent images predominantly within the silver halide grains can beusefully employed in the practice of this invention. Such internallatent image emulsions are disclosed in Davey and Knott U.S. Pat.2,592,250, issued Apr. 8, 1952. The photographic silver halide emulsionsare generally coated in the photographic element at concentrations inthe range of about 250 to about 1,000 mg. of silver per square foot ofsupport. Particularly good results are obtained with elements containinghigh speed X-ray sensitive emulsion layers which are generally coated atcoverages of at least 250 mg. of silver per square foot of support,preferably polyester film support.

The photographic compositions described herein can be coated on a Widevariety of supports in preparing photographic elements. The photographicsilver halide emulsions can be coated on one 'or both sides of thesupport which is preferably transparent and/or flexible. Typicalsupports are cellulose nitrate film, cellulose ester film, polyvinylacetyl film, polystyrene film, polyethylene terephthalate film and otherpolyester film as well as glass, paper, metal, Wood and the like.Supports such as paper which are coated with a-olefin polymers,particularly polymers of a-olefins containing two or more carbon atoms,as exemplified by polyethylene, polypropylene, ethylene-butenecopolymers, and the like, give good results.

The photographic emulsions described herein can be chemically sensitizedwith compounds of the sulfur group, noble metal salts such as goldsalts, reduction sensitized with reducing agents, and combinations ofthese. Furthermore, emulsion layers and other layers present inphotographic elements made according to this invention can be hardenedwith any suitable hardener such as aldehyde hardeners, aziridinehardeners, hardeners which are derivatives of dioxane,oxypolysaccharides such as oxystarch, oxy plant gums, and the like.

The photographic silver halide emulsions can also contain additionaladditives, particularly those known to be beneficial in photographicemulsions, including for example, stabilizers or antifoggants,particularly the water soluble inorganic acid salts of cadmium, cobalt,manganese and zinc as disclosed in U.S. Pat. 2,829,404, the substitutedtriazaindolizines as disclosed in U.S. Pats. 2,444,605 and 2,444,607,speed increasing materials, plasticizers, absorbing dyes, and the like.Sensitizers which give particularly good results in the photographiccompositions disclosed herein are the alkylene oxide polymers which canbe employed alone or in combination with other materials, such asquaternary ammonium salts, as disclosed in U.S. Pat. 2,886,437 or Withmercury com- 8 pounds and nitrogen containing compounds, as disclosed inU.S. Pat. 2,751,299.

The invention described herein can be used with various kinds ofphotographic emulsions. For example, it can be used with X-ray sensitivephotographic silver halide emulsions and other nonspectrally sensitizedemulsions as well as orthochromatic, panchromatic and infrared sensitiveemulsions, particularly those sensitized with merocyanine dyes, cyaninedyes, carbocyanine dyes and the like. Furthermore, this invention can beused with emulsions intended for color photography, for example,emulsions containing color forming couplers or emulsions to be developedby solutions containing couplers or other color generating materials. Inaddition, the invention can be used with emulsions intended for use indiffusion transfer processes which utilize the nondeveloped silverhalide in the non-image areas of the negative to form a positive bydissolving the undeveloped silver halide and precipitating it on areceiving layer in close proximity to the orig inal silver halideemulsion layer. Such processes are described in Rott U.S. Pat.2,352,014, Land U.S. Pat. 2,543,181, and Yackel et al. U.S. Pat.3,020,155. The invention described herein can also be used with colortransfer processes which utilize the diffusion transfer of an imagewisedistribution of developer, coupler or dye from a light sensitive layerto a second layer while the two layers are in close proximity to oneanother. Color transfer processes of this type are described in YutzyU.S. Pat. 2,856,142, Land et al. U.S. Pat. 2,983,606, Whitmore et al.British Pats. 904,364 and 840,731 and Whitmore et al. U.S. applicationSer. No. 392,471, now Pat. No. 3,227,552. Silver halide emulsionscontaining the polymers can be processed in monobath processes such asdescribed in Haist et al. U.S. Pat. 2,875,048 or in stabilization typeprocesses.

In most cases the elfect of kink desensitization is readily visible inthe fresh film coating, but in many cases the elfect is most pronouncedonly after the film has been aged prior to kinking. The antikink markingeffect can be observed by means of a triangle or sensitometric bendtest. The triangle test involves compressing a sample of a film coatingbetween two plates, one of which has a raised triangle and the other ofwhich has a triangle of about three times the area of the first cut init. The raised triangle is an isosceles triangle, the longer sides beingabout inch in length, the shorter side being about inch in length. Theoffset of the raised triangle is about inch and the proportions of thedepressed triangleare the same as those of the raised triangle. Fortesting purposes, a three kilogram weight is applied to the top of theraised triangle. The sensitometric bend test involves bending a strip offilm through an angle of about (the radius of curvature being about inchin most instances), the radius of curvature being great enough so thatthe film strip is not creased. The film, after kinking, is then giveneither a uniform flash or is exposed to an Eastman IB sensitometer anddeveloped, fixed, washed and dried in the usual manner. The spectraldistribution of the light source is adjusted by means of a filter to bealmost identical with that emitted by a standard fluorescent screen suchas is customarily employed in X-ray photography. Of course, when usingthe sensitometric bend test the bending is done longitudinally so thateach step in the exposure by the simulated X-ray screen is crossed bythe line of kinking. The results of the triangle and sensitometric bendtests parallel each other generally. In all instances reported in thefollowing tables the film is aged at F. at 45% relative humidity forthree days before kinking. The results of the sensitometric bend testsare given in the tables below in the columns heated AD aged 3 days at120 F., 50% RH.

The effectiveness of the addenda can be observed by visual comparisonbetween the densities of the unaffected and kinked portions of the film,or by making density measurements therefrom. The densities reported inthe following tables are obtained from sensitometric steps,

the densities of which are 0.40 and 0.90 above gross fog. The differencein density between the normal density of these steps and the density inthe kinked portion is measured and is designated as AD in the followingtables. The effects of the triangle :bend test are observed visually.The effects are rated on the basis of for no kinking, 1 for very slightkinking, 2 for slight kinking, 3 for moderate improvement and 4 for noimprovement. Photographic speed as reported in the following tables isindicated as a function of the exposure necessary to give a density of0.20 above background fog and is relative with respect to the control ineach case.

This invention can be further illustrated by the follow ing examples ofpreferred embodiments thereof although it will be understood that theseexamples are included merely for purposes of illustration and are notintended to limit the scope of the invention unless otherwisespecifically indicated.

EXAMPLE 1 The gelatin, hydrophilic colloid, water insoluble interpolymercombination described herein improves antikink and sensitivity ofphotographic silver halide emulsions. To illustrate, an ordinary coarsegrain gelatino-silver bromoiodide emulsion of the type normally used inradiography which is chemically ripened to optimum sensitivity isdivided into several portions. One portion of the emulsion is untreatedand serves as a Control while Water insoluble copoly (methylacrylate-sodium-4-acryloyloxybutane-sulfonate) (95:5 weight percent)referred to in the following table simply as copolymer and water solublepoly- As shown by the above table, the use of water solublepolyacrylamide as a second hydrophilic colloid with geltin and the watersoluble interpolymer significantly increases photographic speed over thegelatin coating alone as well as over the coatings in which gelatin iscombined with either the water soluble polyacrylamide or water insolublepolymer in the binding material. Furthermore, this speed increase iscombined With good antikink protection.

Similar results are obtained when the above procedure is repeated withother water insoluble interpolymers such as copoly(methylmethacrylate-sodium 3-acryloyloxypropane-l-sulfonate), copoly(methylacrylate-sodium 3- acryloyloxypropane-l-sulfonate), copoly(methylacrylateacrylic acid-sodium 3-acryloyloxypropane-l-sulfonate) andcopoly(methyl acrylate-glycidyl methacrylate-sodium3-acryloyloxypropanel-sulfonate) EXAMPLE 2.

As already indicated, the water insoluble interpolymers described hereincan be incorporated in a layer coated between the silver halide emulsionlayer and the support, preferably an adjacent gelatin layer. Toillustrate, the procedure of Example 1 is repeated except that theportions of emulsion are coated over a gelatin layer containing 200 mg.of gelatin per square foot of support and the copoly(methylacrylate-sodium4-acryloyloxybutane-sulfonate) and polyacrylamide areincorporated in this gelatin layer in the concentrations listed in thefollowing table. Upon testing as described in Example 1 the results areas follows:

TABLE 2 Grams of AD after 3 polymer days, 120 F addenda per 50% R.H

mole of Coating silver halide Speed Gamma Fog 0. 0.90

Control 126 2. 80 13 02 02 Control over gelatin layer (200 mg.gelatin/ft?) 132 2. 90 13 04 06 Control, plus copolymer 25 148 2. 90 1304 05 D 155 3. 00 14 04 04 159 2. 14 02 03 D0 162 2. 85 14 01 0.0Control, plus:

Copolymer 100 200 3. 05 16 0. 0 03 Iolyaerylamide 45 acrylamide(inherent viscosity of 0.30 in water at 25 C.) are incorporated intoanother portion of the gelatin, silver halide photographic emulsion atthe concentrations listed in the following table. Each of the portionsof the photographic emulsion are coated on an ordinary polyester filmsupport at a silver coverage of 484 mg./ft. and a gelatin coverage of535 mg./ft. The coated samples are exposed on an Eastman IB sensitometerand developed for 6 minutes in an ordinary MQ developer such as Kodakdeveloper D-19. After development the samples are fixed, washed anddried in the usual manner. The kink mark desensitization is determinedby the sensitometric bend test described above and the results given inTable 1 are obtained. The speed, gamma, and fog of the emulsion are alsodetermined and the results listed in the following table.

As previously pointed out, water soluble polyacrylamides are thepreferred hydrophilic colloids to be used in combination with gelatinand the water insoluble interpolymers when practicing this invention.However, other hydrophilic colloids with gelatin and water solubleinterpolymer give both an increase in speed and anti-kink protection. Toillustrate, succinoylated polyvinyl alcohol, as described in Minsk andAbel US. Pat. 3,165,412, issued Jan. 12, 1965, is added to one portionof an ordinary coarse grain gelatino-silver bromoiodide emulsioncontaining 200 g. of gelatin per mole of silver halide and 100 g. ofcopoly(methyl acrylate-sulfopropyl acrylate) (95:5 weight percent). Oneportion of the emulsion is untreated and serves as the control. Eachportion of the emulsion is coated on an ordinary polyethyleneterephthalate film support at a silver coverage of 450 mg./ft The coatedTABLE 1 Grams of AD after 3 polymer days, F., addenda per 60% R.H.

mole of Coating silver halide Speed Gamma Fog 0. 40 0. 90

ControL 123 3.00 .12 -.06 11 Control, plus eopolymer 2. 85 14 03 03 D0174 2.45 .21 Control, plus polyacrylamide 159 3. 25 14 01 05 C ontrol,plus:

Copolymer 20 Polyacrylamide 45 2. 90 19 03 06 Copolymer 60Polyacrylamide 45 214 2. 65 24 02 04 TABLE 3 Grams of polymer per moleAgX Speed Gamma Fog Kink Coating:

A 100 l. 03 03 4 B 50 129 1. 30 01 2 In addition to reduced kink-markdesensitization, the coatings obtained using the above procedure alsoexhibit increased D,,,,,,, in areas unaffected by kink.

EXAMPLE 4 The procedure of Example 3 is repeated with a coarse graingelatino-silver bromoiodide emulsion using dextran (Coating B), asdescribed in US. Pat. 3,063,838, issued Nov. 13, 1962, andpoly-N-vinyl-Z-pyrrolidone (Coating C). Coating A is the untreatedcontrol. After testing as in Example 3 the following results areobtained:

TABLE 4 Grams of polymer per mole AgX Speed Gamma Fog Kink Coating:

A 100 l. 05 01 4 B .u 50 186 l. 25 02 2 C 50 115 l. 30 01 1 Thus, by thepractice of this invention there is provided photographic emulsions andelements exhibiting improved anti-kink and sensitivity. This is achievedby using, in photographic silver halide emulsions and elements, a uniquecombination of gelatin, a second hydrophilic colloid and water insolublepolymer as described herein. The novel combination is particularlyuseful in emulsions intended for use in radiography but the combinationis also useful in any coated film where a tendency towarddesensitization as a result of kinking is exhibited and where anincrease in speed is desired.

Although the invention has been described in considerable detail withreference to certain preferred embodiments thereof, it will beunderstood that variations and modifications can be effected withoutdeparting from the spirit and scope of the invention as describedhereinabove and as defined in the appended claims.

We claim:

1. A photographic silver halide emulsion comprising (A) awater-insoluble interpolymer of (l) at least about 65%, by weight, ofunits of a monomer having the formula:

wherein R is a hydrogen atom or a methyl group and R is alkyl, (2) unitsof a monomer having the formula:

i OHz=(|JC-ORg-SO3M R7 in a concentration of up to about 20%, by weight,wherein R is a hydrogen atom or an alkyl, R has its valence bondsrepresented in the above formula on different carbon atoms and is adivalent hydrocarbon radical or a divalent aliphatic hydrocarbon radicalin which the chain of carbon atoms joining the oxygen and sulfur atomsin the above formula is interrupted by an oxygen or sulfur 12 atom, andM is a cation, and (3) 0 to about 20%, by Weight, of units ofethylenically unsaturated monomer that is copolymerizable With anddifferent from (1) and (2); (B) gelatin; and (C) at least one otherhydrophilic colloid.

2. A photographic element comprising a support and at least one layer ofthe photographic silver halide emulsion according to claim 1.

3. A photographic silver halide emulsion comprising (A) about 5 to about100 grams per mole of silver halide of a water-insoluble interpolymer of(1) about to about by weight, of units of a monomer having the formula:

where R is a hydrogen atom or a methyl group and R is alkyl, (2) about 5to about 15%, by weight, of units of a monomer having the formula:

where R; is a hydrogen atom or an alkyl, R has its valence representedin the above formula on different carbon atoms and is a divalenthydrocarbon radical or a divalent aliphatic hydrocarbon radical in whicha chain of carbon atoms joining the oxygen and sulfur atoms of the aboveformula is interrupted by an oxygen or sulfur atom and M is a cation and(3) 0 to about 10%, by weight, of ethylenically unsaturated monomer thatis copolymerizable with and different from (1) and (2); (B) gelatin; and(C) about 5 to about 80%, by Weight, based on said gelatin of at leastone other hydrophilic colloid.

4. A photographic element comprising (A) a support; (B) at least onegelatin, photographic silver halide emulsion layer containing at leastone other hydrophilic colloid; and (C) incorporated in at least onelayer, which is contiguous to or in close proximity to the said silverhalide emulsion layer, a water-insoluble interpolymer of (l) at leastabout 65 by weight, of units of a monomer having the formula:

wherein R is a hydrogen atom or a methyl group and R is alkyl, (2) unitsof a monomer having the formula:

in a concentration of up to about 20%, by weight, wherein R is ahydrogen atom or an alkyl, R; has its valence bonds represented in theabove formula on different carbon atoms and is a divalent hydrocarbonradical or a divalent aliphatic hydrocarbon radical in which the chainof carbon atoms joining the oxygen and sulfur atoms in the above formulais interrupted by an oxygen or sulfur atom, and M is a cation, and (3) 0to about 20%, by Weight, of units of ethylenically unsaturated monomerthat is copolymerizable with and different from (1) and (2).

5. A photographic element according to claim 4 wherein said silverhalide emulsion layer comprises about 5 to about 80%, by weight, basedon said gelatin of said other hydrophilic colloid.

6. A photographic element according to claim 4 comprising from about 5to about grams per mole of silver halide in said element of saidwater-insoluble polymer.

7. The photographic element of claim 4 in which said water-insolubleinterpolymer is in a gelatin layer contiguous to said emulsion layer.

8. The photographic element of claim 4 in which the support is aflexible support, said other hydrophilic colloid is water-solublepolyacrylamide having an inherent viscosity in the range of about 0.1 toabout 0.6 and said water-insoluble interpolymer has a molecular weightin the range of about 5,000 to about 50,000.

9. The photographic element of claim 4 in which said water-insolubleinterpolymer is a water-insoluble interpolymer of (1) about 85 to about95%, by weight, of units of an alkyl acrylate and (2) about 5 to about15%, by weight, of units of a monomer having the formula:

10. The photographic element of claim 4 in which the water-insoluble isa water-insoluble interpolymer of (1) about 85 to about 95%, by weight,of methyl acrylate and (2) about 15 to about 5%, by weight, of sodium-3-acryloyloxybutane-l-sulfonate.

11. The photographic element of claim 4 in which said other hydrophiliccolloid is succinoylated polyvinyl alcohol.

12. The photographic element of claim 4 in which said other hydrophiliccolloid is poly-N-vinylpyrrolidone.

13. A photographic element comprising a polyester film support, an X-raysensitive gelatin photographic silver halide emulsion layer on each sideof said support containing about 5 to about 80%, by weight, based on thegelatin, of water-soluble polyacrylamide, and incorporated in at leastone layer, which is no farther from said support than said emulsionlayer, a water-insoluble interpolymer of about 85 to about 95 by weight,of 1) units of an alkyl acrylate and (2) about 5 to about 15%, byweight, of units of a monomer having the formula:

where Rq is hydrogen, R has its valence bonds represented in the aboveformula on different carbon atoms and is a divalent hydrocarbon radicaland M is an alkali metal.

14. A photographic element of claim 13 in which said polyester supportis polyethylene terephthalate.

15. A photographic element comprising a support, at least one gelatinphotographic silver halide emulsion layer containing about to about 80%,by weight, based on the gelatin, of a water-soluble polyacrylamidehaving an inherent viscosity in the range of about 0.1 to about 0.6 andincorporated in at least one layer, which is contiguous to or in closeproximity to the said emulsion layer, about 5 to about 100 grams permole of silver halide of a waterinsoluble interpolymer of 1) about 85 toabout 95% by weight, of units of a monomer having the formula:

where R is a hydrogen atom or a methyl group and R is alkyl, (2) about 5to about 15%, by weight, of units of a monomer having the formula:

where R, is a hydrogen atom or an alkyl group, R has its valence bondsrepresented in the above formula on different carbon atoms and is adivalent hydrocarbon radical or divalent aliphatic hydrocarbon radicalin which a chain of carbon atoms joining the oxygen and sulfur atoms ofthe above formula is interrupted by an oxygen or sulfur atom and M is acation and (3) 0 to about 10%, by weight, of ethylenically unsaturatedmonomer that is copolymerizable with and different from (1) and (2).

16. A photographic element comprising a flexible support, at least onegelatin, photographic silver halide emulsion layer containing about 5 toabout by weight, based on the gelatin, of a water-insolublepolyacrylamide which has an inherent viscosity in the range of about 0.1to about 0.6, and incorporated in at least one layer, which iscontiguous to or in close proximity to the said emulsion layer, awater-insoluble interpolymer of (1) about to about by weight, of methylacrylate and (2) about 15 to about 5%, by weight, of sodium-3-acryloyloxypropane sulfonate.

References Cited UNITED STATES PATENTS 3,241,969 3/1966 Hart et a196--l14 RONALD H. SMITH, Primary Examiner US. Cl. X.R. 96-114

